The host galaxy of GRB 980425/SN1998bw: A collisional ring galaxy

M. Arabsalmani*, S. Roychowdhury, T. K. Starkenburg, L. Christensen, E. Le Floc'h, N. Kanekar, F. Bournaud, M. A. Zwaan, J. P.U. Fynbo, P. Møller, E. Pian

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

16 Scopus citations


We report Giant Metrewave Radio Telescope (GMRT), Very Large Telescope (VLT), and Spitzer Space Telescope observations of ESO 184−G82, the host galaxy of GRB 980425/SN 1998bw, that yield evidence of a companion dwarf galaxy at a projected distance of 13 kpc. The companion, hereafter GALJ193510-524947, is a gas-rich, star-forming galaxy with a star formation rate of 0.004 M yr−1, a gas mass of 107.1±0.1 M, and a stellar mass of 107.0±0.3 M. The interaction between ESO 184−G82 and GALJ193510-524947 is evident from the extended gaseous structure between the two galaxies in the GMRT H I 21 cm map. We find a ring of high column density H I gas, passing through the actively star-forming regions of ESO 184−G82 and the GRB location. This ring lends support to the picture in which ESO 184−G82 is interacting with GALJ193510-524947. The massive stars in GALJ193510-524947 have similar ages to those in star-forming regions in ESO 184−G82, also suggesting that the interaction may have triggered star formation in both galaxies. The gas and star formation properties of ESO 184−G82 favour a head-on collision with GALJ193510-524947 rather than a classical tidal interaction. We perform state-of-the-art simulations of dwarf-dwarf mergers and confirm that the observed properties of ESO 184−G82 can be reproduced by collision with a small companion galaxy. This is a very clear case of interaction in a gamma-ray burst host galaxy and of interaction-driven star formation giving rise to a gamma-ray burst in a dense environment.

Original languageEnglish (US)
Pages (from-to)5411-5422
Number of pages12
JournalMonthly Notices of the Royal Astronomical Society
Issue number4
StatePublished - Mar 13 2019


  • Galaxies: ISM
  • Galaxies: interactions
  • Galaxies: kinematics and dynamics
  • Galaxies: star formation
  • Gamma-ray burst: general
  • Radio lines: galaxies

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


Dive into the research topics of 'The host galaxy of GRB 980425/SN1998bw: A collisional ring galaxy'. Together they form a unique fingerprint.

Cite this